Or a company can make a certain important product with no competition via collusion and other means, which are well known to anyone with even a cursory understanding of history. The end result can be quite the same. That's what monopolies do. It is trivial to show how your assertions are false.
No cartel had ever win with collusion in the marketplace. They all eventually self-destruct.
"Anti-trust" laws are used against smaller companies rather than large corporations because it is easier to bully smaller companies into submission.
Then the government turns around and give companies monopolies via patents and copyright. Now, they have a much easier time to maintain their cartel.
Government doesn't protect competition. It squashes competition.